Platelet Count and POC PT/INR

A participant asks if point of care PT/INR results are affected by the platelet count.

George responds that POC PT/INR instrument package inserts list no effects related to thrombocytopenia or thrombocytosis. Documented interferences include specimen management errors that result in partial preanalytical clotting, foaming, or hemolysis; hematocrit below 20% or above 55%, presence of coagulopathies not related to Coumadin effects as may be encountered in liver disease; and presence lupus anticoagulant. These are approximately the same interferences that could affect standard plasma-based PT/INR results.